/*
 * Copyright 2010 - 2011, The PLDesktop Development Team
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */

#include <stdlib.h>
#include <math.h>

char cvtbuf[CVTBUFSIZE];

extern "C" char *cvt(double arg, int ndigits, int *decpt, int *sign, char *buf, int eflag) {
	int r2;
	double fi, fj;
	char *p, *p1;
	if (ndigits < 0) {
		ndigits = 0;
	}
	if (ndigits >= CVTBUFSIZE - 1) {
		ndigits = CVTBUFSIZE - 2;
	}
	r2 = 0;
	*sign = 0;
	p = &buf[0];
	if (arg < 0) {
		*sign = 1;
		arg = -arg;
	}
	arg = modf(arg, &fi);
	p1 = &buf[CVTBUFSIZE];
	if (fi != 0) {
		p1 = &buf[CVTBUFSIZE];
		while (fi != 0) {
			fj = modf(fi / 10, &fi);
			*--p1 = (int)((fj + .03) * 10) + '0';
			r2++;
		}
		while (p1 < &buf[CVTBUFSIZE]) {
			*p++ = *p1++;
		}
	} else if (arg > 0) {
		while ((fj = arg * 10) < 1) {
			arg = fj;
			r2--;
		}
	}
	p1 = &buf[ndigits];
	if (eflag == 0) {
		p1 += r2;
	}
	*decpt = r2;
	if (p1 < &buf[0]) {
		buf[0] = '\0';
		return buf;
	}
	while (p <= p1 && p < &buf[CVTBUFSIZE]) {
		arg *= 10;
		arg = modf(arg, &fj);
		*p++ = (int) fj + '0';
	}
	if (p1 >= &buf[CVTBUFSIZE]) {
		buf[CVTBUFSIZE - 1] = '\0';
		return buf;
	}
	p = p1;
	*p1 += 5;
	while (*p1 > '9') {
		*p1 = '0';
		if (p1 > buf) {
			++*--p1;
		} else {
			*p1 = '1';
			(*decpt)++;
			if (eflag == 0) {
				if (p > buf) {
					*p = '0';
				}
				p++;
			}
		}
	}
	*p = '\0';
	return buf;
}
